The story of London gangsters Reginald (Tom Hardy, left) and Ronnie Kray is told f|Simon Mein

The gangster movie is in a tough spot now. A genre that thrives on mythology, built on tales either embellished or frighteningly real, now finds itself in an era when we want the real deal — when even our superheroes must be dragged down to gritty, grimy earth. But real gangsters’ lives are as messy as everyone else’s, which is to say not easily condensed into a movie’s mere two hours-and-change. And so we get “Black Mass” and now “Legend,” two tales of larger-than-life underworld gods, and two films that sputter around without focus through epic, convoluted stories crammed as nuts and fruit and goo are into a KIND bar.

Plowing through a decade of criminal tomfoolery in the lives of East End Londoners Ronnie and Reginald Kray, “Legend” can’t find a solid in — all the more shocking as it’s from Brian Helgeland, who won an Oscar for cracking James Ellroy’s sprawling tome “L.A. Confidential.” But it has a good hook. Or at least it has the right actor and a gimmick that feels novel but not cheap. It gives you double the Tom Hardy, cast as both the suave Reg and the Cro-Magnon Ron, the latter a paranoid schizophrenic lifted from a much-needed psych ward stint through his brother’s nudge-nudgey influence.

The Krays’ story is narrated by Reg’s increasingly disillusioned, waifish wife Frances (Emily Browning), but it’s really a Greatest Hits collection. There’s the time they brought a hammer to a bar fight. There’s the time Ron shot a guy in a packed bar. There’s the time they beat each other up in public. (The latter is done with some nifty POV shots, with one Tom Hardy assaulting the camera, then switching over to the other Tom Hardy doing the same.)

There’s a lot to get through, but there’s no angle, no way of organizing it around an idea. We get hints of something more concentrated. Occasionally it feels it might turn into a gangland version of David Cronenberg’s “Dead Ringers,” in which two Jeremy Ironses slowly and devastatingly began melding into a single self-destructive unit. But Helgeland keeps having to attend to the real, overly complex events, plugging away until his villains are either in jail or dead.

Still, if “Legend” has no shape, and if the lack of a driving force makes it feel “Godfather”-long, at least it has a sense of humor. The Krays’ rise in London’s underworld may be hopelessly muddled — exacerbated by Hardy’s now trademark mushy-mouthed delivery as both heroes — but it’s told as some wished “Black Mass” had: as a dark comedy. Tonally it’s joined at the hip with its weirdo double-barreled star.

Hardy really does give two performances — indeed the twin extremes of his versatility. Reg is all movie star charisma, fitted with the actor’s defiant sing-song delivery. Meanwhile, and usually in the same scene, awkward loose cannon Ron rattles off indecipherable monologues in impenetrable geysers of pure noise.

Hardy’s the movie’s ace in the hole — the thing it can always fall back on when the story gets too knotted-up and when the movie eventually feels like it will never end. One can pass most of “Legend” just grooving on the concentrated Hardy-ness. He makes it easier to give up on the Wikipedia structure, ignore its tepid attempts to turn Frances into anything but a motive-less cipher. Hardy’s twin turn is the kind of stunt ones forgets is a stunt while still marveling at its audacity, even while mourning for a time when the same story would have worked best as a movie, not as a Netflix TV series.